Wireless communications systems are used in a variety of telecommunications systems, television, radio and other media systems, data communication networks, and other systems to convey information between remote points using wireless transmitters and wireless receivers. A transmitter is an electronic device which, usually with the aid of an antenna, propagates an electromagnetic signal such as radio, television, or other telecommunications. Transmitters often include signal amplifiers which receive a radio-frequency or other signal, amplify the signal by a predetermined gain, and communicate the amplified signal. On the other hand, a receiver is an electronic device which, also usually with the aid of an antenna, receives and processes a wireless electromagnetic signal. In certain instances, a transmitter and receiver may be combined into a single device called a transceiver.
Receivers include a number of components that are arranged to convert a received wireless signal, usually in the radio-frequency spectrum, to a digital signal capable of being processed by digital circuitry (e.g., microprocessors, digital signal processors, etc.). Typically, a component known as an analog-to-digital converter (ADC) is used to perform such conversion. Recently, a specific type of ADC known as a delta-sigma ADC has been increasingly applied in many applications. A delta-sigma ADC includes a one or more component blocks often referred to as a delta-sigma modulator. Each delta-sigma modulator may subtract an output feedback signal from an input signal, and mathematically integrate the difference to produce an output signal. A delta-sigma ADC may include one or more of such delta-sigma modulators oriented in a serial manner, and a delta-sigma ADC may be referred to as an nth-order delta-sigma ADC, wherein n equals the number of delta-sigma modulators.
A particular type of delta-sigma ADC is known as an incremental ADC, wherein each integrator of the ADC is reset after each conversion cycle, such that the ADC is reset and ready to accept the next sample. This incremental feature provides a one-to-one mapping between input and output after each conversion and makes the ADC suitable for multi-channel operation.
Despite their advantages, incremental ADCs may have disadvantages. For example, traditional continuous time incremental ADCs may have long conversion times, especially compared to their discrete time counterparts. In addition, traditional incremental ADCs may have many linear and direct-current (DC) offset errors due to non-idealities of the ADC.